In this month's Physics World: Juno vs Jupiter – the spacecraft battling against the biggest planet in the solar system

4 July 2016

Science writer Stephen Ornes discusses the perilous world that awaits the Juno spacecraft as it arrives at the doorstep of the gaseous giant.

Next week Juno will latch onto the gravitational pull of the biggest planet in the solar system, and in doing so, risk life and solar-panel-clad limb to uncover the secrets hidden beneath the clouds of Jupiter.

In July’s Physics World, we explore the secrets of the solar system in this special planetary science issue. Science writer Stephen Ornes speaks to experts working on the Juno mission to explain why Jupiter could answer some of the biggest questions of the solar system, but the planet may not divulge them as readily as we might like.

Even though Juno has been hurling towards the planet for five years now, once the spacecraft reaches the planet, the real challenge will be dodging the threatening radiation bands that menacingly circle Jupiter to enter its atmosphere.

“You’ve got this stream of electrons and protons circling the planet, and they’re lethal to spacecraft,” says astronomer and Juno team member Tobias Owen of the University of Hawaii. “Until now, spacecraft have been farther out. We’re going to be inside it.”

Jupiter’s magnetosphere, the largest known structure in our solar system, is a constant stream of high-energy protons and electrons; the radiation has claimed casualties in the past as instruments on other crafts have failed as they’ve been caught in the radioactive outbursts.

With Juno scheduled to fly from pole to pole along a path that will reduce radiation exposure, and also boasting centimetre-thick titanium walls, the team is hoping that this mission will be free from complications caused by the magnetosphere and Juno will be able to collect data about the planet’s mysterious hydrogen oceans, clouds, atmosphere and core.

“The thing that’s most exciting to me is the determination of water deep in the atmosphere,” says Owen. “By measuring the water we’ll get an idea of the way that Jupiter came together.”

It seems that for Juno, the stakes are high: the overall aim of the mission is not just to find out more about Jupiter, but to start to understand the origins of the solar system too.

Says Scott Bolton, Juno’s principal investigator, “When you want to understand where we all came from and how the planets were made, you have to start with Jupiter.”

Want to read on? This article from Physics World is available in PDF form upon request, and can also be read online by those with IOP membership.

Also in this special issue on planetary science:

Planet Nine: Konstantin Batygin on why he and astronomer Mike Brown propose there is a ninth planet in our solar system